Conventionally, there is known a fastening tool, in which a projection for provisional fastening is provided on a hole edge of an insertion hole of a grommet to project toward the inside of the insertion hole, and an elastic arm part to be elastically caught on the aforementioned projection is provided on a tip part of a shaft part of a pin (for example, see paragraph [0016] and FIG. 4 of Patent Document 1).
Specifically, the projection for provisional fastening on the grommet is elastically caught between a base of the elastic arm part of the pin and a projection positioned below (for example, see paragraph [0016] and FIG. 4 of Patent Document 1).